The Fourth Workshop on Vitamin D is scheduled to be held February 18-22, 1979 in Berlin (West) Germany. It is anticipated that some 300-400 scientists from the disciplines of chemistry, biochemistry, physiology, as well as clinicians with a variety of specialities will be in attendance at this meeting. (The Third Workshop on Vitamin D held in January, 1977 at Asilomar, California was attended by 332 registered delegates.) The purposes of this grant application are to request funds to support the travel of approximately 9-12 invited American speakers to attend the Fourth Workshop on Vitamin D as well as funds to support the travel of 9-14 American "Younger Scientists" in the general area of calcium and phosphorus homeostasis (including vitamin D, parathyroid hormone, calcitonin) to attend the Fourth Worshop on Vitamin D. The funds used to support the travel of the invited speakers will be distributed over the complete spectrum of scientific disciplines contributing to the formal program while funds used to support "Younger Scientists" will be distributed in accordance with these same scientific disciplines. Applications for support from "Younger Scientists" will be received and reviewed by a subcommittee of the 30-person Workshop Advisory Committee (composed of scientists in all disciplines).